The present invention pertains to a device for turning continuously transported, flat lying printed products.
In the manufacture of books, brochures, book blocks or similar bound printed products, the required processing machines are coupled to one another by means of conveying devices such that assembly lines are formed, wherein the printed products are usually transported in a flat lying fashion. Reorientations during the transport are carried out in order to realize a different product position for ensuing processing steps. It is known to transfer the printed products from a feed conveyor that transports the printed products in a first direction to a delivery conveyor that is arranged underneath the feed conveyor and extends in the opposite transport direction such that the printed products are additionally transported after they are turned in the transport plane by 180° referred to the transport direction.
In one known device for turning printed products that are flexible to a certain degree, the printed products are transported with a minimum speed from the feed conveyor into a vertically arranged and downwardly extending path guide slide that is essentially arranged tangentially downstream of the feed conveyor and realized in a semicircular or C-shaped fashion, wherein the printed products adjoin the inwardly curved guideway under the influence of the centrifugal force. In this case, the printed products are turned by 180° about an axis that extends parallel to the leading edge such that they are turned from their upper side to their lower side and the leading edge remains unchanged. At the outlet of the slide, the printed products are transferred to a delivery conveyor that is essentially arranged tangentially downstream of the slide and extends in the opposite direction of the feed conveyor situated above the delivery conveyor.
This turning device has a simple constructive design. With the exception of the feed conveyor and the delivery conveyor, this turning device features no drives and also requires no controlled elements. However, it is disadvantageous that the printed products need to have a minimum speed at the inlet such that they do not fall off the slideway due to their gravitational force. However, this results in a very high speed at the outlet such that the printed products continue to slide on the slower delivery conveyor and the distances between successively transported printed products are not defined. Particularly asymmetric weight and/or stiffness distributions in the printed products as they occur, for example, with printed products that are fed longitudinally referred to the bound spine result in greater turning in the respective transport plane while the printed products slide on the inwardly curved guideway. This may result in product alignments at the outlet that are turned by 45° or more and can only be corrected with costly auxiliary devices.